The best thing to do when markets falls is to buy the coins as much as you can at a cheaper level. Patience is a virtue.The time will come when these coins will give you profits more than your expectations.
You can sell your coins to buy coins that fall deep enough so that you will get a lot of coins so that if the coin goes up you will get a big profit. but it is very risky because it is not easy for coins to rise quickly and there are many dead projects so you have to be careful if you want to do it.